Fluid and Electrolyte Balance - PNUR201 - PDF

PRESBYTERIAN UNIVERSITY, GHANA FACULTY OF HEALTH AND MEDICAL SCIENCES DEPARTMENT OF NURSING AND MIDWIFERY PNUR201: MEDICAL NURSING I A. B. FRANK  FLUIDS AND ELECTROLYTES  ▪ Discuss the various physiological processes that accomp...

PRESBYTERIAN UNIVERSITY, GHANA FACULTY OF HEALTH AND MEDICAL SCIENCES DEPARTMENT OF NURSING AND MIDWIFERY PNUR201: MEDICAL NURSING I A. B. FRANK  FLUIDS AND ELECTROLYTES  ▪ Discuss the various physiological processes that accomplish homeostasis in the body. ▪ Name the fluid compartments, the fluids contained in them, and the function of those fluids. OBJECTIVES ▪ Describe the way the kidneys work to maintain fluid and electrolyte balance. ▪ Explain hypervolaemia and hypovolaemia  ▪ The external environment within which we live undergoes continual changes, both small and large. ▪ In order for life to continue, however, our internal environment—the one inside our bodies—must remain relatively constant, varying only slightly within narrow ranges. INTRODUCTION ▪ This internal environment consists of the various body fluids such as the fluid inside cells, the blood, tissue fluids that bathe the cells, and other fluids. ▪ Maintenance of the internal environment within very narrow limits is termed homeostasis (equilibrium).  ▪ Human life is suspended in a saline solution having a salt concentration of 0.9%. ▪ This solution, which both surrounds the cells and is contained within them, constitutes the body fluids. BODY FLUIDS ▪ The water and electrolytes composing these body fluids come from ingested water and nutrients, and from the water that results from metabolism.  ▪ Much of the body weight of an average adult is due to the water in the body fluids surrounding the cells and contained within them. BODY FLUIDS ▪ The fluid around the cells cushions them and serves as the medium of exchange. ▪ Everything that enters or leaves the cells must pass through this fluid layer.  Body fluid is located in two compartments: ▪ the intracellular space (fluid in the cells) ▪ the extracellular space (fluid outside the cells) FLUID o The extracellular fluid (ECF) compartment is further COMPARTMENTS divided into the intravascular, interstitial, and transcellular fluid spaces. ▪ The intravascular space (the fluid within the blood vessels) contains plasma.  ▪ The interstitial space contains the fluid that surrounds the cell and totals about 11 to 12 L in an adult ▪ The transcellular is smallest division of the ECF compartment and contains approximately 1 L of fluid FLUID at any given time. Examples of transcellular fluid are cerebrospinal, pericardial, synovial, intraocular, and COMPARTMENTS pleural fluids ▪ Body fluid normally shifts between the two major compartments or spaces in an effort to maintain an equilibrium between the spaces  ELECTROLYTES Electrolytes in body fluids are active chemicals (cations, which carry positive charges, and anions, which carry negative charges) In a solution, cations and anions are equal in mEq/L. The body expends a great deal of energy maintaining the high extracellular concentration of sodium and the high intracellular concentration of potassium.  CATION QUANTITY Sodium 142 Potassium 5 Calcium 5 Magnesium 2 TOTAL 154 ANIONS QUANTITY EXTRACELLULAR Chloride 103 Bicarbonate 26 FLUID Phosphate 2 Sulfate 1 Organic acid 5 Proteinate 17 TOTAL 154  CATION QUANTITY Potassium 150 Magnesium 40 Sodium 10 TOTAL 200 INTRACELLULAR ANIONS QUANTITY FLUID Phosphates and sulfates 150 Bicarbonate 10 Proteinate 40 TOTAL 200  ▪ Water and ions moving between the extracellular and intracellular fluids must first pass through the MOVEMENT OF selectively permeable cell membrane. FLUID AND ▪ This movement is governed primarily by ELECTROLYTES osmosis. ▪ Diffusion and active transport also play a role.  ▪ The difference in the ion concentration inside the cell and outside the cell is due primarily to the cell’s ability to pump some ions inside and pump others out. ▪ If the intracellular fluid becomes hypertonic to the MOVEMENT OF extracellular fluid, water from the extracellular fluid will move by osmosis into the cell to restore the FLUID AND balance and vice versa. ELECTROLYTES ▪ A fluid balance also occurs between the interstitial fluid and the plasma. ▪ This balance is regulated primarily by hydrostatic pressure (blood pressure) and osmotic pressure.  ▪ There must be a balance in the amounts of fluids and electrolytes consumed and lost daily. FLUID AND ▪ Under typical conditions, the average adult loses some ELECTROLYTE water through the skin, lungs, and GI tract and loses the largest amount of water through urine production. BALANCE ▪ This can amount to a per-day fluid loss of approximately 2,500 mL, depending on conditions.  ▪ Skin ▪ Lungs ▪ GI Tract FLUID AND ▪ Kidneys (ADH, Renin Angiotensin system, ELECTROLYTE Aldosterone) BALANCE ▪ Glands (Thyroid, Parathyroid) ▪ Fluid and food intake ▪ Thirst  ▪ Fluid and electrolyte balance is essential for health. ▪ Many factors, such as illness, injury, surgery, and FLUID AND treatments, can disrupt a patient’s fluid and electrolyte balance. ELECTROLYTE ▪ Even a patient with a minor illness is at risk for fluid IMBALANCES and electrolyte imbalance. FLUID VOLUME DEFICIT  HYPOVOLAEMIA This describes a situation where intake of fluid is less than loss of extracellular fluid when water and electrolytes are lost in the same proportion as they exist in normal body fluids, so that the ratio of serum electrolytes to water remains the same. Dehydration refers to a fluid loss of 1% or more of body weight.  Fever with poor oral intake Prolonged inadequate intake of fluids/ food HYPOVOLAEMIA AETIOLOGY Abnormal fluid losses, such as those resulting from vomiting, diarrhoea, GI suctioning, and sweating Risk factors include diabetes insipidus, adrenal insufficiency, osmotic diuresis, and hemorrhage.  acute weight decreased postural HYPOVOLAEMIA loss; skin turgor; hypotension; CLINICAL MANIFESTATIONS weak, rapid flattened heart rate; neck veins;  ▪ decreased central venous pressure; HYPOVOLAEMIA ▪ cool, clammy skin related to peripheral CLINICAL vasoconstriction; MANIFESTATIONS ▪ thirst; anorexia; nausea; ▪ lassitude; muscle weakness; and cramps.  HYPOVOLAEMIA DIAGNOSIS BUN increases Haematocrit level increases Physical assessment/Health History  ▪ Correct underlying cause ▪ When the deficit is mild, the oral route is preferred, HYPOVOLAEMIA provided the patient can drink MEDICAL ▪ When fluid losses are acute or severe, however, the MANAGEMENT IV route is required. ▪ Isotonic electrolyte solutions such as NS and R/L.  ▪ Monitor I & O ▪ Daily body weight monitoring HYPOVOLAEMIA ▪ Monitor vital signs hourly until patient is stable NURSING ▪ Monitor skin turgor MANAGEMENT ▪ Monitor mental functioning ▪ Monitor for manifestations of shock  Burke, K., LeMone, P., & Mohn-Brown, L. (2011). Medical- surgical nursing care (3rd ed.). Upper Saddle River, NJ: Prentice-Hall. REFERENCES Grodner, M., Roth, S. L., & Walkingshaw, B. C. (2012). Nutritional foundations and clinical applications: A nursing approach (5th ed.). St. Louis, MO: Mosby.